As an initial part of the structure-function investigation of cytochrome P-450, we propose to determine the amino acid sequence of the Pseudomonas putida protein. Since the mammalian cytochrome P-450 is only starting to be obtained in a highly purified form and since they are complex lipoproteins, the P. putida cytochrome P-450 will act as a model cytochrome P-450 for some years to come. The amino acid sequence of the Cu-subunit of bovine heart cytochrome oxidase has been initiated and will be completed. Studies will be performed to determine the Cu-binding sites in the protein which at the present time appear to be cysteine residues.